1. Field of the Invention
The present invention relates to a delivery system for delivering printing plates or machine plates to a position near a printing press to place the printing plates in a stand-by state. More specifically, the invention relates to a printing plate delivery system for such printing plates to be used in a printing press, in which a plurality of printing stages are arranged in vertically to form a multi-stage printing press.
2. Description of the Related Art
Printing plate delivery systems have been known as disclosed in Japanese Unexamined Patent Publications Nos. Showa 59-165659 and Showa 60-52343, for example. The delivery systems disclosed in the above-identified publications includes a transporting system extending from a plate processing station to a position near a printing press for transporting processed printing plates to stack near the printing press.
On the other hand, Japanese Unexamined Patent Publication No. Heisei 3-184849 discloses a printing plate delivery system for delivering printing plates to respectively designated plate cylinders in respective vertically-arranged printing stages in the printing press, such as a blanket-to-blanket type printing press. The disclosed system includes a robot arm having an operation head, which is reciprocally movable along an axis of a vertical guide and pivotable about the vertical guide axis for supplying printing plates for the plate cylinders in respective vertically-arranged printing stages located at both sides of the vertical guide.
The above-mentioned conventional printing plate delivery systems are not satisfactory in application for a type of printing press where a plurality of printing stages are arranged vertically for forming a multi-stage printing press. Namely, the delivery systems disclosed in Japanese Unexamined Patent Publications Nos. Showa 59-165659 and Showa 60-52343 are adapted to transport the printing plates to a position near respective ones of the printing presses arranged on a common floor level. Therefore, these printing plate delivery systems have not been designed to deliver the printing plates to vertically-arranged printing stages in the printing press and thus cannot deliver the printing plate to the convenient positions for loading on the plate cylinders in respective vertically-arranged printing stages.
Accordingly, loading of the printing plate on the plate cylinders in the upper printing stages has to be performed manually by personnel by manually bringing the plates to the corresponding floor levels. This requires a substantial work load in carrying the printing plates up and down between the upper and lower floors and thus is quite labor intensive. Furthermore, such manual transportation of the printing plates between a plurality of height levels of floors inherently requires substantial attention for work security. In view of work efficiency and security, improvement has been strongly required.
On the other hand, the printing plate delivery system disclosed in Japanese Unexamined Patent Publication No. Heisei 3-184849 solves the problems the work load and improves work efficiency and security. However, such delivery system requires precision and complex mechanism and relatively highly precise control and thus is quite expensive. Furthermore, such system requires maintenance at relatively high frequency to cause increasing of running cost.